Diflubenzuron and related insecticides, as disclosed, for example, by De Milo et al in J. Agric. Food Chem. Vol. 26, No. 1, p. 164-6 (1978) present a problem with respect to obtaining good distribution on plants and assuring effective contact with insects. For the most part, these insecticides do not have systemic activity. They are deposited on the surface of plant foliage and must be eaten by chewing insects in order to be effective. If the particle size of the deposited material is too large, insects may be able to avoid ingesting fatal amounts until they have done considerable damage.
Belgian Pat. No. 868,228 discloses a class of dihalobenzoylurea insecticides which, when applied on older foliage of a plant, for example a soya plant, will be transferred within the soya plant up to newer shoots of the plant. However, there is no transfer of the insecticide through the plant when the compound is applied to roots of soya or other plants.